Widely available digital media players such as DVD players typically employ fast playback of program material to cue the user during fast forward or fast rewind activities. However, such fast playback often involves a rapid presentation of all or some of the program material in its sped-up form which is difficult for the viewer to digest and comprehend.
Some advanced DVD players move through the program material so fast during fast playback that continuous fast video is impossible, and instead, short fragments of motion are shown for perhaps a second or fraction of a second, while skipping intervening program material until the next fragment is displayed. This involves real-time generation and display of selected frames taken directly from the digital media, and hence requires additional processing power by the media player. Further, such fast playback mode does not offer the user the ability to enter a navigation mode, and then at their leisure step from frame to frame, without feeling pressure to focus intently on the rapidly moving picture in order to arrest motion at the desired point—an activity that may generate anxiety and distract from the enjoyment of watching the program.
DVD movies provide chapter navigation functions in which chapters may be represented in a screen display by still images taken from the DVD program and a user may navigate among the images using a DVD remote control to select a chapter by selecting its associated image. These still images are prepared manually under editorial control and very few (typically less than 20) still images serve as chapter identifiers for the typical DVD movie. Further, the chapter navigation still images often do not represent the video content of a frame at which a chapter actually begins, but are seen at later points in the chapter that are considered representative of the chapter.
In addition to digital media players such as DVDs, streaming media delivery techniques are now widely used for delivery of short video clips, music, and audio files over a data network. However, present techniques for moving rapidly through streaming video files are awkward and inconvenient.
Typically, downloading or launching a streaming media file over a network such as the Internet causes a user's computer to invoke a media player application, such as QuickTime, Windows Media Player, RealAudio, etc. In the media player application, the streaming media file is represented as a slider control typically displayed below a video window or audio visualizer. To move from the beginning of the media file to a point far in the future, the user slides the slider control and waits for the media file to play. However, before starting playback, the media player must download and buffer data of the media file at or just preceding the requested playback point and cannot display the content at or ahead of that point until buffering is complete. Thus, the user normally must wait at least a short time before playback occurs.
Further, the user cannot see ahead into the content in a fast forward operation and cannot rapidly see frames, images or streams of data earlier in a rewind operation; each such operation requires moving the slider, waiting for downloading and buffering, followed by playback at normal speed.
When the entire media file is very large, such as a 2-hour movie, and when the user desires to fast forward to a point 1 hour from the start of the movie, the amount of time involved in receiving and buffering is unacceptably long.
Thus, streaming video and streaming audio protocols do not provide an inherent mechanism for performing “trick play” functions such as fast forward and fast rewind. Each connection of a user device to a media server or other program source has a physical maximum transfer rate, and if a user were to attempt to obtain data at faster than that rate, the server could not deliver data at the requested rate. The data formats used for streaming video and streaming audio do not inherently permit performing fast forward or fast rewind functions, or fast-forward and rewind at different speeds.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.